Avoid the creation of too many strings in 'package'
Both when setting a path and searching for a file ('searchpath'),
this commit reduces the number of intermediate strings created
in Lua.
(For setting a path the change is not relevant, because this is
done only twice when loading the module. Anyway, it is a nice example
of how to use auxlib buffers to manipulate strings in the C API.)
diff --git a/lgc.h b/lgc.h
index 9ba7ecb..b972472 100644
--- a/lgc.h
+++ b/lgc.h
@@ -127,7 +127,7 @@
/*
** some gc parameters are stored divided by 4 to allow a maximum value
-** larger than 1000 in a 'lu_byte'.
+** up to 1023 in a 'lu_byte'.
*/
#define getgcparam(p) ((p) * 4)
#define setgcparam(p,v) ((p) = (v) / 4)
diff --git a/llimits.h b/llimits.h
index cc98397..febf755 100644
--- a/llimits.h
+++ b/llimits.h
@@ -39,7 +39,7 @@
/* maximum value for size_t */
#define MAX_SIZET ((size_t)(~(size_t)0))
-/* maximum size visible for Lua (must be representable in a lua_Integer */
+/* maximum size visible for Lua (must be representable in a lua_Integer) */
#define MAX_SIZE (sizeof(size_t) < sizeof(lua_Integer) ? MAX_SIZET \
: (size_t)(LUA_MAXINTEGER))
diff --git a/loadlib.c b/loadlib.c
index 4cf9aec..ff73a45 100644
--- a/loadlib.c
+++ b/loadlib.c
@@ -290,22 +290,33 @@
static void setpath (lua_State *L, const char *fieldname,
const char *envname,
const char *dft) {
+ const char *dftmark;
const char *nver = lua_pushfstring(L, "%s%s", envname, LUA_VERSUFFIX);
- const char *path = getenv(nver); /* use versioned name */
- if (path == NULL) /* no environment variable? */
+ const char *path = getenv(nver); /* try versioned name */
+ if (path == NULL) /* no versioned environment variable? */
path = getenv(envname); /* try unversioned name */
if (path == NULL || noenv(L)) /* no environment variable? */
lua_pushstring(L, dft); /* use default */
- else {
- /* replace ";;" by ";AUXMARK;" and then AUXMARK by default path */
- path = luaL_gsub(L, path, LUA_PATH_SEP LUA_PATH_SEP,
- LUA_PATH_SEP AUXMARK LUA_PATH_SEP);
- luaL_gsub(L, path, AUXMARK, dft);
- lua_remove(L, -2); /* remove result from 1st 'gsub' */
+ else if ((dftmark = strstr(path, LUA_PATH_SEP LUA_PATH_SEP)) == NULL)
+ lua_pushstring(L, path); /* nothing to change */
+ else { /* path contains a ";;": insert default path in its place */
+ size_t len = strlen(path);
+ luaL_Buffer b;
+ luaL_buffinit(L, &b);
+ if (path < dftmark) { /* is there a prefix before ';;'? */
+ luaL_addlstring(&b, path, dftmark - path); /* add it */
+ luaL_addchar(&b, *LUA_PATH_SEP);
+ }
+ luaL_addstring(&b, dft); /* add default */
+ if (dftmark < path + len - 2) { /* is there a sufix after ';;'? */
+ luaL_addchar(&b, *LUA_PATH_SEP);
+ luaL_addlstring(&b, dftmark + 2, (path + len - 2) - dftmark);
+ }
+ luaL_pushresult(&b);
}
setprogdir(L);
lua_setfield(L, -3, fieldname); /* package[fieldname] = path value */
- lua_pop(L, 1); /* pop versioned variable name */
+ lua_pop(L, 1); /* pop versioned variable name ('nver') */
}
/* }================================================================== */
@@ -421,17 +432,26 @@
}
-static const char *pushnextfilename (lua_State *L, const char *path) {
- const char *l;
- if (*path == *LUA_PATH_SEP)
- path++; /* skip separator */
- if (*path == '\0')
+/*
+** Get the next name in '*path' = 'name1;name2;name3;...', changing
+** the ending ';' to '\0' to create a zero-terminated string. Return
+** NULL when list ends.
+*/
+static const char *getnextfilename (char **path, char *end) {
+ char *sep;
+ char *name = *path;
+ if (name == end)
return NULL; /* no more names */
- l = strchr(path, *LUA_PATH_SEP); /* find next separator */
- if (l == NULL) /* no more separators? */
- l = path + strlen(path); /* go until the end */
- lua_pushlstring(L, path, l - path); /* file name */
- return l; /* rest of the path */
+ else if (*name == '\0') { /* from previous iteration? */
+ *name = *LUA_PATH_SEP; /* restore separator */
+ name++; /* skip it */
+ }
+ sep = strchr(name, *LUA_PATH_SEP); /* find next separator */
+ if (sep == NULL) /* separator not found? */
+ sep = end; /* name goes until the end */
+ *sep = '\0'; /* finish file name */
+ *path = sep; /* will start next search from here */
+ return name;
}
@@ -442,12 +462,12 @@
** no file 'blublu.so'
*/
static void pusherrornotfound (lua_State *L, const char *path) {
- if (*path == *LUA_PATH_SEP)
- path++; /* skip separator */
- lua_pushstring(L, "\n\tno file '");
- luaL_gsub(L, path, LUA_PATH_SEP, "'\n\tno file '");
- lua_pushstring(L, "'");
- lua_concat(L, 3);
+ luaL_Buffer b;
+ luaL_buffinit(L, &b);
+ luaL_addstring(&b, "\n\tno file '");
+ luaL_addgsub(&b, path, LUA_PATH_SEP, "'\n\tno file '");
+ luaL_addstring(&b, "'");
+ luaL_pushresult(&b);
}
@@ -455,17 +475,24 @@
const char *path,
const char *sep,
const char *dirsep) {
+ luaL_Buffer buff;
+ char *pathname; /* path with name inserted */
+ char *endpathname; /* its end */
+ const char *filename;
/* separator is non-empty and appears in 'name'? */
if (*sep != '\0' && strchr(name, *sep) != NULL)
name = luaL_gsub(L, name, sep, dirsep); /* replace it by 'dirsep' */
- /* replace marks ('?') in 'path' by the file name */
- path = luaL_gsub(L, path, LUA_PATH_MARK, name);
- while ((path = pushnextfilename(L, path)) != NULL) {
- const char *filename = lua_tostring(L, -1);
+ luaL_buffinit(L, &buff);
+ /* add path to the buffer, replacing marks ('?') with the file name */
+ luaL_addgsub(&buff, path, LUA_PATH_MARK, name);
+ luaL_addchar(&buff, '\0');
+ pathname = luaL_buffaddr(&buff); /* writable list of file names */
+ endpathname = pathname + luaL_bufflen(&buff) - 1;
+ while ((filename = getnextfilename(&pathname, endpathname)) != NULL) {
if (readable(filename)) /* does file exist and is readable? */
- return filename; /* return that file name */
- lua_pop(L, 1); /* else remove file name */
+ return lua_pushstring(L, filename); /* save and return name */
}
+ luaL_pushresult(&buff); /* push path to create error message */
pusherrornotfound(L, lua_tostring(L, -1)); /* create error message */
return NULL; /* not found */
}
diff --git a/testes/main.lua b/testes/main.lua
index b9dcab1..aab490c 100644
--- a/testes/main.lua
+++ b/testes/main.lua
@@ -142,12 +142,18 @@
prepfile("print(package.path, package.cpath)")
RUN('env LUA_INIT="error(10)" LUA_PATH=xxx LUA_CPATH=xxx lua -E %s > %s',
prog, out)
+ local output = getoutput()
+ defaultpath = string.match(output, "^(.-)\t")
+ defaultCpath = string.match(output, "\t(.-)$")
+
+ -- running with an empty environment
+ RUN('env -i lua %s > %s', prog, out)
local out = getoutput()
- defaultpath = string.match(out, "^(.-)\t")
- defaultCpath = string.match(out, "\t(.-)$")
+ assert(defaultpath == string.match(output, "^(.-)\t"))
+ assert(defaultCpath == string.match(output, "\t(.-)$"))
end
--- paths did not changed
+-- paths did not change
assert(not string.find(defaultpath, "xxx") and
string.find(defaultpath, "lua") and
not string.find(defaultCpath, "xxx") and
@@ -160,15 +166,20 @@
RUN('env LUA_PATH="%s" lua %s > %s', p, prog, out)
local expected = getoutput()
expected = string.sub(expected, 1, -2) -- cut final end of line
- assert(string.gsub(p, ";;", ";"..defaultpath..";") == expected)
+ if string.find(p, ";;") then
+ p = string.gsub(p, ";;", ";"..defaultpath..";")
+ p = string.gsub(p, "^;", "") -- remove ';' at the beginning
+ p = string.gsub(p, ";$", "") -- remove ';' at the end
+ end
+ assert(p == expected)
end
convert(";")
convert(";;")
-convert(";;;")
-convert(";;;;")
-convert(";;;;;")
-convert(";;a;;;bc")
+convert("a;;b")
+convert(";;b")
+convert("a;;")
+convert("a;b;;c")
-- test -l over multiple libraries
